Photodiode and method for making the same

Abstract

A method for manufacturing a photodiode including the steps of providing a substrate, solution depositing a quantum nanomaterial layer onto the substrate, the quantum nanomaterial layer including a number of quantum nanomaterials having a ligand coating, and applying a thin-film oxide layer over the quantum nanomaterial layer.

What is claimed is: 
     
       1. A photodiode comprising:
 a substrate comprising doped germanium and a sulfur-passivated surface; 
 a solution-cast quantum nanomaterial layer positioned on said sulfur-passivated surface of said substrate, 
 said solution-cast quantum nanomaterial layer comprising a plurality of quantum nanomaterials tuned to absorb radiation within a bandwidth of mid-wavelength infrared and long-wavelength infrared, 
 each quantum nanomaterial of said plurality of quantum nanomaterials comprising: 
 a core comprising tin-telluride; 
 a ligand coating on said core, said ligand coating comprising a metal chalcogenide complex, comprising at least one of tin-sulfide, tin-selenide and tin-telluride; and 
 a thin-film oxide layer over said solution-cast quantum nanomaterial layer. 
 
     
     
       2. The photodiode of  claim 1  wherein said germanium is doped p-type germanium. 
     
     
       3. The photodiode of  claim 1  wherein each quantum nanomaterial of said plurality of quantum nanomaterials has a maximum cross-sectional dimension between 15 nanometers and 50 nanometers. 
     
     
       4. The photodiode of  claim 1  wherein said thin-film oxide layer comprises an amorphous oxide semiconductor. 
     
     
       5. The photodiode of  claim 1  further comprising a first contact layer on said thin-film oxide layer. 
     
     
       6. The photodiode of  claim 5  further comprising a second contact layer on said substrate. 
     
     
       7. A photodiode comprising:
 a substrate comprising doped germanium and a sulfur-passivated surface; 
 a solution-cast quantum nanomaterial layer positioned on said sulfur-passivated surface of said substrate, 
 said solution-cast quantum nanomaterial layer comprising a plurality of quantum nanomaterials tuned to absorb radiation within a bandwidth of mid-wavelength infrared and long-wavelength infrared, 
 each quantum nanomaterial of said plurality of quantum nanomaterials comprising: 
 a core comprising lead-tin-telluride; 
 a ligand coating on said core, said ligand coating comprising a metal chalcogenide complex, comprising at least one of tin-sulfide, tin-selenide and tin-telluride; and 
 a thin-film oxide layer over said solution-cast quantum nanomaterial layer. 
 
     
     
       8. The photodiode of  claim 7  wherein said germanium is doped p-type germanium. 
     
     
       9. The photodiode of  claim 7  wherein each quantum nanomaterial of said plurality of quantum nanomaterials has a maximum cross-sectional dimension of at least 7.5 nanometers. 
     
     
       10. The photodiode of  claim 7  wherein said thin-film oxide layer comprises an amorphous oxide semiconductor. 
     
     
       11. The photodiode of  claim 7  further comprising a first contact layer on said thin-film oxide layer. 
     
     
       12. The photodiode of  claim 11  further comprising a second contact layer on said substrate.